Learn the ABCs about GMOs
FACT SHEET: GENETICALLY ENGINEERED FOODS
Questions and Health Concerns
What are genetically engineered (GE) foods?
These are foods created from the insertion of a gene, bacteria or virus from one species into a different species to produce a desired effect, usually resistance to herbicides or insects. The terms genetically modified (GM) and genetically modified organisms (GMO’s) are typically used interchangeably with GE.
Are they the same as foods from traditional breeding?
No. Traditional breeding between the same or similar species, such as crossing two types of corn or apples, has been done for thousands of years. GE foods, only developed in the past few decades, are created in a lab and are between different species.
What kinds of food are genetically engineered?
There are currently six major foods sold in the U.S. that are typically genetically engineered. These are listed below with the percent that are GE:
Sugar beets 95%
Cotton (Cottonseed oil) 78%
Because most of these are used widely, about two-thirds of processed food contains a GE ingredient. Conversely, the vast majority of raw fruits and vegetables are not GE. Organic foods, by definition, can’t be GE.
Does genetic engineering improve the nutritional quality of foods?
No. There are no GE foods on the market in which nutritional quality is enhanced beyond a non-GE food counterpart.
Is the act of genetic engineering precise?
No. The entire foundation of GE is that the introduction of one foreign gene, bacteria or virus into a plant will activate one protein, producing one desired effect and nothing more. But this ignores basic science – the chances of harmful unintended consequences with GE are substantially increased:[i]
One gene often creates multiple proteins
- The location of the gene often varies, which can affect whether it produces the desired protein or not
- The insertion of the gene can disrupt the genetic blueprint of the plant
- The new gene can either silence other genes that were normally active or activate other genes that were silent
- A promoter (typically a virus) is usually added that helps the gene activate a desired protein. However, it may also activate other proteins that were silent, which could lead to harmful effects on humans.
What evidence of harmful effects are there?
The deadliest incident occurred in the food supplement l-tryptophan, which had been used safely by millions of people as a sleep aid for decades. However, when a Japanese company produced a GE version in the late 1980’s, thousands of people contracted an extremely painful, serious disease, EMS, that killed at least 37 and left thousands with disabilities, including paralysis.[ii] The FDA subsequently removed virtually all l-tryptophan off the market, although only the GE version was linked to EMS.
It’s more difficult to detect harmful conditions such as cancer, birth defects, toxins or allergies, since they have other causes and/or can take longer to develop than EMS. Moreover, the FDA doesn’t require GE foods to be labeled, so most people don’t know they’re consuming them. This makes it virtually impossible to isolate and track them.
However, numerous credible animal studies all over the world have shown disturbing results. For example:
- In Scotland, GE potatoes fed to rats showed lowered nutritional content and suffered damaged immune systems, smaller brains, livers and testicles and enlarged intestines[iii]
- In Australia, a harmless gene in a bean engineered into a pea produced immune reactions in mice, indicating allergic reactions and/or toxins[iv]
- In Austria, a government study showed that mice fed GE corn had fewer litters and fewer total offspring[v]
- In France, a study found that GE corn previously thought harmless revealed hormone-dependent diseases and early signs of toxicity in rats[vi]
Harm to animals doesn’t necessarily prove harm to humans. However, it is a definite indication that more studies should be done. This hasn’t happened.
How is safety testing done in the U.S.? Is it adequate?
The FDA is responsible for food safety. However, it doesn’t do any testing on GE food and doesn’t require any independent tests. The only studies done are by the same companies developing the foods and they’re not required to give all their data to the FDA. They only need to declare their studies are adequate and that the GE food is safe. By and large, GE food safety is self-regulated.
The bottom line
Plants can be genetically engineered to be resistant to pests or herbicides. But in the process, there is evidence they may be causing harm to human health as an unintended consequence.
[i] Commoner, Barry, Unraveling the DNA Myth: The Spurious Foundation of Genetic Engineering, Harper’s, Feb. 2002.
[ii] Crist, William, Toxic L-tryptophan: Shedding Light on a Mysterious Epidemic, 2005, available at http://www.seedsofdeception.com/Public/L-tryptophan/1Introduction/index.cfm.
[iii] Ewen, SW, Pusztai, A, Effect of diets containing genetically modified potatoes expressing Galanthus nivalis lectin on rat small intestine, Lancet, Oct. 16, 1999, 354(9187): 1353-4.
[iv] Prescott, V et al, Transgenic Expression of Bean α-Amylase Inhibitor in Peas Results in Altered Structure and Immunogenicity, Journal of Agricultural and Food Chemistry, 2005, 53:9023-9030.
[v] For the full study in English, see http://bmgfj.cms.apa.at/cms/site/attachments/3/2/9/CH0810/CMS1226492832306/forschungsbericht_3-2008_letzfassung.pdf
[vi] Seralini, G-E et al, How Subchronic and Chronic Health Effects can be Neglected for GMO’s, Pesticides or Chemicals; International Journal of Biological Sciences, 2009, 5(5): 438-443.
This Fact Sheet is provided by: Oregon Physicians for Social Responsibility, www.oregonpsr.org.